Does anyone have any experience interpreting test-negative approaches to vaccine effectiveness? Pic/link related. I feel like I'm losing my mind, or maybe I'm just a complete brainlet. Please note I'm not trying to deboonk any of this I just need help understanding.
https://www.cdc.gov/mmwr/volumes/70/wr/mm7037e2.htm?s_cid=mm7037e2_w
I can understand how test-negative approaches have worked in principle in the past for people studying influenza vaccines: you have a large cohort of people who have been to a clinic or hospital for treatment for influenza-like illness (ILI). You test them all for influenza using pcr or w/e. Your positive test results are your cases and the negative test results are your controls. This works because a large number of people with ILI will test negative for influenza, as they are symptomatic for any other number of respiratory infections, so you end up with more controls than cases, and you can do some simple statistics based on the vaccination rates between your two groups and come up with some estimate of vaccine effectiveness.
What I cannot for the life of me understand is how this approach is being applied to covid-19 infections/vaccines, such as in table 1 from this recent CDC report.
They find that, of 6,960 unvaccinated people who were hospitalized for covid-19, 1,316 had a positive test result for the virus. Whereas of 7,676 unvaccinated people hospitalized for covid-19, only 235 had a positive test result. Which begs the question, if among these 14,636 combined total people hospitalized for covid, only 1,551 (10.5%) tested positive for the virus, what the fuck did the other 89.5% of people have if not covid? In the middle of a global pandemic with hundreds of thousands of people dying, among the people being hospitalized for presumed covid-19 infections, only 10 fucking percent actually test positive for the virus?
I know that I have to be reading this wrong but I don't know how. Someone please help?
[internal message visible to mods only]
Quoted By:
delete this immediately janny
Anonymous
>recent CDC report
Anonymous
>>13634111 It's just just the CDC there are other papers/preprints out there of people using the test-negative design to study the covid vaccines. I feel like this can't just be the result of garbage data, I mean my first thought is that the PCR tests they are using have to be extremely poor to find that only ~10% of people hospitalized for covid-19 actually have the virus. But it can't just be the tests, since there is clear indications in their data that the number of positive tests in the vaccinated group is truly lower than the unvaccinated group, so there is definitely something there.
But still what the fuck is going on that so many people are being hospitalized for the covid and yet testing negative for it? I must be reading the data wrong right?
Anonymous
Quoted By:
they are lying to you
Anonymous
>>13634118 But it has to be garbage data.
They're not testing vaccinated people for COVID even though they should. Even if you pick someone else, they can only work with the same info that the CDC has.
Anonymous
Quoted By:
>>13634118 *it's not just the CDC
They describe in the paper that the test results up to 14 days prior to or 3 days after hospitalization were accepted, so it's possible that they have so few positive results due to the fact that the test was given before they actually had covid, if I'm reading that right... but why the fuck would they do that?
"Among people hospitalized for covid, many of them had a negative test result 14 days before dying to the virus" what does that tell me? absolutely nothing.
Anonymous
>>13634101 >In the middle of a global pandemic with hundreds of thousands of people dying, among the people being hospitalized for presumed covid-19 infections, only 10 fucking percent actually test positive for the virus? >I know that I have to be reading this wrong but I don't know how. Someone please help? Help with what? Are you asking how people test negative? Because tests are not perfect, because people that take test are not perfect, because it's too late or too early to get a proper sample from the certain sampling point the country uses for testing...
Pretty much in every civilized country people are hospitalized based on symptoms not positive test.
Anonymous
Quoted By:
>>13634128 That's not how these test-negative studies work, they are testing EVERYONE hospitalized for covid-19 for the virus and only looking at vaccination status afterwards.
I just don't understand why they have so many negative test results among people hospitalized for presumed covid.
Anonymous
>>13634155 >Are you asking how people test negative? Yes
>Because tests are not perfect, because people that take test are not perfect, because it's too late or too early to get a proper sample from the certain sampling point the country uses for testing... No, the entire point of a test-negative approach to vaccine effectiveness is that they have to be TRUE negatives, not false negatives due to poor testing. If you are saying that all of those negatives are false negatives, then these estimates they are coming up with for vaccine effectiveness are absolutely meaningless, right?
Anonymous
>>13634174 >No, the entire point of a test-negative approach to vaccine effectiveness is that they have to be TRUE negatives, not false negatives due to poor testing. If you are saying that all of those negatives are false negatives, then these estimates they are coming up with for vaccine effectiveness are absolutely meaningless, right? I have no idea how you constructed that, it's statistics based on available data. I just told you why PCR tests may fail, because that's what you asked. The number of tests failed because someone left machine on for too long or for too short, is probably irrelevant to number of tests failed because they were taken too early or too late.
Whatever reasons is that PCR tests fail, it's applicable both to vaccinated and unvaccinated because there is no difference in testing these 2 groups, so your premise that it's meaningless is wrong.
Anonymous
Quoted By:
>>13634203 Ok, so while the vast majority of these are false negatives due to poor testing, there are some true negatives in there as well which allows for comparison between case/controls?
I think that could be one way to make sense of the data. It's just surprising to me to see that 90% of the people hospitalized for covid-19 test negative for the virus, I feel like that is something that should be addressed somehow. If anything I assumed the tests were biased towards low specificity resulting in false positives, but it really depends what cycle threshhold they were using I guess.
Anonymous
>>13634203 It still kind of begs the question in my mind, if we are saying some of these are true negatives (allowing for comparison between vaccinated vs unvaccinated), what the hell are these people being hospitalized for if not covid-19? Influenza maybe? All of the estimates for influenza I've seen have shown that the virus is hardly prevalent at all.
Why are there so many vaccinated people being hospitalized with covid-like symptoms who are actually negative for the virus (more often then unvaccinated people), and what are they actually suffering from? Is it just that common for people to show up at hospitals with these similar symptoms of unknown etiology?
Anonymous
>>13634101 Am I reading this right? Despite more vaccinated than unvaccinated people being hospitalized with COVID-like symptoms, 'vaccine effectiveness' is claimed to be high just because a smaller proportion of them ends up yielding a positive PCR result? That's wild.
Where does the data on hospitalization according to vaccination status come from? It would be very interesting to see data on all-cause morbidity/mortality by vaccination status. If COVID is a big deal and the vaccines are effective, we would expect hospitalizations for COVID-like illness to account for a substantial proportion of overall hospitalization, and the unvaccinated to make up a very disproportionate share of those hospitalized.
But at least according to this data, from a time when less than half the population was fully vaccinated, there were about as many vaccinated as unvaccinated hospitalized for COVID-like illness, differences in PCR results notwithstanding. What about hospitalization rates for reasons other than COVID-like illness? Any vaxxchads brave enough to see what we may find there?
Anonymous
Quoted By:
>>13634296 The PCR cycle threshold is lower (stricter) for breakthrough cases in the USA, which might explain why a smaller proportion of the vaccinated with COVID-like symptoms test positive, but that doesn't seem to be the full story because it leaves unanswered the mystery of why, if 'vaccine effectiveness' as defined here is an artifact of different testing criteria, there is a difference between the different types of vaccines.
Even if it turns out that the vaccines defeat the PCR test and not the virus, maybe the booster meme is still true and there is a difference between how well they do so and/or for how long?
Anonymous
>>13634692 You are aware that most of the vulnerable population that ends up in hospitals is vaccinated?
Fucking /pol/ tourists
Anonymous
Quoted By:
>>13634946 This isn't about 'is' but 'was', in particular during the time span in question. I can't find a timeline for vaccination rate by age for the us, but it would have to be close to 100% to be compatible with the narrative about vaccine protection from severe disease, and it's not even close. And given that they're lying about the upsides of the vaccines, they're almost certainly lying about the downsides as well. But fortunately, this matte4 should be easy to settle based on data the CDC evidently possesses. So again, what is the all-cause morbidity/mortality by vaccination status? Why are we only seeing rates of COVID that don't even track with the rates of COVID-like illness? Let's be honest, if the raw data painted as rosy a picture of the vaccines as they they want us to believe, it would be blasted across every channel and not obfuscated by these definitional games.
Anonymous
Quoted By:
>>13634101 Brainlet here, I could be totally wrong but here's my understanding: once your body figures out the virus and you've got T-cells roaming around it doesn't take long to clear up a viral infection. Most of the symptoms of viruses are the downsides of immune response or recovering from the massive damage caused by both the infection and the purge. By then time you're hospitalized most people will already have killed the virus and are suffering from the after effect of the infection so there often won't be enough virus in your system to actually give a positive test.
It is interesting that vaccinated patients test positive at higher rates though, especially with the much lower PCR cycle count. It could be that these vaccines reduce symptoms by slowing the immune response so it takes longer to clean up the infection? That would explain the high viral load in vaccinated hosts.
Anonymous
Quoted By:
This kind of data makes me hestitant about the vaccine, it doesn't seem to have any positive impact, we just had a big spike of cases when the vaccine was suppose to diminish it.
